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authorNeilBrown <neilb@suse.de>2022-05-10 04:20:49 +0300
committerakpm <akpm@linux-foundation.org>2022-05-10 04:20:49 +0300
commit5169b844b7dd5934cd4f22ab66de0cc669abf0b0 (patch)
tree97adf12221bb1191c14dafc9aae6713586060a55 /mm/swap.h
parentcba738f6490953e154d163b2980ad6d7f06307aa (diff)
downloadlinux-5169b844b7dd5934cd4f22ab66de0cc669abf0b0.tar.xz
mm: submit multipage reads for SWP_FS_OPS swap-space
swap_readpage() is given one page at a time, but may be called repeatedly in succession. For block-device swap-space, the blk_plug functionality allows the multiple pages to be combined together at lower layers. That cannot be used for SWP_FS_OPS as blk_plug may not exist - it is only active when CONFIG_BLOCK=y. Consequently all swap reads over NFS are single page reads. With this patch we pass in a pointer-to-pointer when swap_readpage can store state between calls - much like the effect of blk_plug. After calling swap_readpage() some number of times, the state will be passed to swap_read_unplug() which can submit the combined request. Link: https://lkml.kernel.org/r/164859778127.29473.14059420492644907783.stgit@noble.brown Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swap.h')
-rw-r--r--mm/swap.h17
1 files changed, 14 insertions, 3 deletions
diff --git a/mm/swap.h b/mm/swap.h
index eafac80b18d9..0389ab147837 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -7,7 +7,15 @@
/* linux/mm/page_io.c */
int sio_pool_init(void);
-int swap_readpage(struct page *page, bool do_poll);
+struct swap_iocb;
+int swap_readpage(struct page *page, bool do_poll,
+ struct swap_iocb **plug);
+void __swap_read_unplug(struct swap_iocb *plug);
+static inline void swap_read_unplug(struct swap_iocb *plug)
+{
+ if (unlikely(plug))
+ __swap_read_unplug(plug);
+}
int swap_writepage(struct page *page, struct writeback_control *wbc);
void end_swap_bio_write(struct bio *bio);
int __swap_writepage(struct page *page, struct writeback_control *wbc,
@@ -41,7 +49,8 @@ struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
unsigned long addr,
- bool do_poll);
+ bool do_poll,
+ struct swap_iocb **plug);
struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,
unsigned long addr,
@@ -56,7 +65,9 @@ static inline unsigned int page_swap_flags(struct page *page)
return page_swap_info(page)->flags;
}
#else /* CONFIG_SWAP */
-static inline int swap_readpage(struct page *page, bool do_poll)
+struct swap_iocb;
+static inline int swap_readpage(struct page *page, bool do_poll,
+ struct swap_iocb **plug)
{
return 0;
}